The proposed project has four major goals: (1) to examine in a large representative community sample the strength of the association between a history of psychological trauma and elevated levels of peculiar perceptions and beliefs, assessed by measuring symptoms of schizotypal personality disorder; (2) to examine whether the effects of neurodevelopmental factors and psychological trauma on vulnerability to peculiar perceptions and beliefs are additive or interactive; (3) to examine the relation between peculiar perceptions and beliefs and disturbances in emotional awareness and the processing and utilization of emotionally-valenced information; and (4) to examine psychological mechanisms (disturbances in emotional awareness and the processing and utilization of emotionally-valenced information, dissociation, absorption, and an intuitive-experiential thinking style) that may mediate the links between distal vulnerability factors, such as psychological trauma and neurodevelopmental factors, and the later development of elevated levels of peculiar perceptions and beliefs. The association between trauma history and schizotypal personality disorder will be examined in a telephone survey of 1500 individuals randomly selected from the community. The remaining goals will be addressed by conducting intensive laboratory/interview assessments of 300 individuals, recruited via telephone screening and newspaper advertising, intentionally oversampling individuals with high levels of schizotypal symptoms. The laboratory/interview assessments will include the assessment of minor physical anomalies, handedness, dermatoglyphic asymmetries, Cluster A personality disorders, childhood maltreatment as well as other traumas, and questionnaire and behavioral measures of the processing and utilization of emotionally-valenced information. The proposed project will improve our understanding of the nature and etiology of schizotypal, schizoid, and paranoid personality disorders. The proposed project will also provide clues concerning which psychological mechanisms might contribute to peculiar perceptions and beliefs across the psychiatric spectrum, such as the hallucinations and delusions exhibited by individuals with psychotic and mood disorders.